Practice question

Induction describes fundamental process where one embryonic tissue, acting as inducer, influences developmental fate of neighboring responding tissue via diffusible or contact-mediated chemical signals. Inducer secretes growth factors such as FGF, BMP antagonists like Noggin, Chordin and Wnt modulators that bind receptors on competent responder, initiating signal transduction cascades like MAPK and Smad that alter gene regulatory networks redirecting differentiation. Classic demonstration is Spemann organizer graft inducing host ectoderm to form neural plate rather than epidermis. Induction may be permissive, enabling self-differentiation, or instructive, actively specifying new fate, underlying tissue interaction.